thickness = 2;
ext = 10;
module whole_wall() {
    cube([thickness, 45, 45 + ext], center = true);
}

module small_wall() {
    cube([thickness * 2 + 1, 10, 8], center = true);
}
module hole_in_small_wall() {
    cube([thickness + 1, 6, 8], center = true);
}

module bottom_door() {
    cube([thickness, thickness, 5], center = true);
}

difference () {
    translate([0, 0, (45 + ext)/2])whole_wall();
    translate([0, 5, 2 + 5/2])bottom_door();
    translate([0, -5, 2 + 5/2])bottom_door();
}
difference () {
    translate([3, 0, ext + 8/2])small_wall();
    translate([2.5, 0, ext + 8/2])hole_in_small_wall();
}

